CODEWITHSUNDEEP
javascriptarrayssorting
Kalreg
Kalreg

Reputation: 1012

how to create an array of sorted indexes by value in object

I have mutlriple objects called stations. Each station has a property called money.

stations[0].money = 2000
stations[1].money = 500
stations[2].money = 1200
stations[3].money = 2200

I want to create an array of stations indexes (0,1,2 and 3 in this example) but sorted by ammount of money each station has ascending by money. So I want to have:

var moneyArray = [1, 2, 0, 3]

what is the most elegant way to do it?

Upvotes: 3

Views: 78

Answers (3)

Bergi
Bergi

Reputation: 664767

You can start with a normal array of indices (loop-generated, preferably) and sort that by the value of the object at the respective index in your stations array:

[0, 1, 2, 3].sort(function(ai, bi) {
    return stations[ai].money - stations[bi].money;
})

Upvotes: 3

Rajshekar Reddy
Rajshekar Reddy

Reputation: 18997

By using a Temp variable you can do it this way. Else if you can afford to modify the main data then the temp variable can be eliminated.

var stations = [{money :2000},{money :500},{money :1200},{money :2200}]

var tempArray = stations.slice();

tempArray.forEach(function (value, i) {
    value.index = i;
});

tempArray.sort(function(a, b){return a.money-b.money});

var finalResult = tempArray.map(function(a) {return a.index;});

document.write(JSON.stringify(finalResult));

Upvotes: 0

Nina Scholz
Nina Scholz

Reputation: 386660

You may have a look here: Sorting with map

// the array to be sorted
var stations = [
        { money: 2000 },
        { money: 500 },
        { money: 1200 },
        { money: 2200 },
    ];

// temporary array holds objects with position and sort-value
var mapped = stations.map(function (el, i) {
    return { index: i, value: el.money };
})

// sorting the mapped array containing the reduced values
mapped.sort(function (a, b) {
    return a.value - b.value;
});

// container for the resulting order
var result = mapped.map(function (el) {
    return stations[el.index];
});

// get the wanted keys
var keys = mapped.map(function (el) {
    return el.index;
});

document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');
document.write('<pre>' + JSON.stringify(keys, 0, 4) + '</pre>');

Upvotes: 1

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